// 1.类型别名
var ret3 = '123';
ret3 = 123;
ret3 = "abc";
// 2.字面量(字符串，数字，布尔)
var str = 'name';
var number = 1;
var bool = false;
// let toWhere: Directions = 输入的时候提示 Directions内容
var toWhere = "Up";
var person = { name: '123', age: 123 };
